Just did some testing with the dozen or so titles (mostly Koei Tecmo musous) I have that require very specific GE Proton versions due to the video codec regressions that occurred awhile back and that GE10-12 finally addresses. The results were a mixed bag, but this is definitely a positive and long-overdue step. A few games were able to shed their late 8.x/early 9.x requirements finally, but others (particularly those released 2015 or earlier) still have the same problems and have to rely on pretty old GE versions.
Samurai Warriors 5 and Warriors Orochi 3 still need GE9-2, Samurai Warriors 4-II and One Piece Pirate Warriors 3 still need GE8-25, and both Dynasty Warriors 8 and DW8 Empires still need GE7-55.
Buuuut Samurai Warriors 4 DX, Samurai Warriors Spirit of Sanada, Warriors Orochi 4, Warriors All-Stars, and One Piece Pirate Warriors 4 all got successfully bumped up. And in non-musou land Pinball FX and Postal Brain Damaged did too.